Industrial Machinery Repair Part 2 pot

Fundamental Requirements of Effective Preventive/Predictive Maintenance 19
4 Calibration interval and when due;
5 Calibration procedures and necessary controls;
6 Actual values of latest calibration;
7 History of maintenance and repairs.
Test equipment and measurement standards should be labeled to indicate
the date of last calibration, by whom it was calibrated, and when the next
calibration is due. When the size of the equipment limits the application of
labels, an identifying code should be applied to reflect the serviceability and
due date for the next calibration. This provides a visual indication of the cali-
bration serviceability status. Both the headquarters calibration organization
and the instrument user should maintain a two-way check on calibration.
A simple means of doing this is to have a small form for each instrument with
a calendar of weeks or months (depending on the interval required) across
the top, which can be punched and noticed to indicate the calibration due
date.
Planning and Estimating
Planning is the heart of good inspection and preventive maintenance. As
described earlier, thefirstthingto establish is what items must be maintained
and what the best procedure is for performing that task. Establishing good
procedures requires a good deal of time and talent. This can be a good
activity for a new graduate engineer, perhapsas part of a training process that
rotates him or her through various disciplines in a plant or field organization.
This experience can be excellent training for a future design engineer.
Writing ability is an important qualification, along withpragmatic experience
in maintenance practices. The language used should be clear and concise,
using short sentences. Who, what, when, where, why, and how should be
clearly described. The following points should be noted from this typical
procedure:
1 Every procedure has an identifying number and title;
2 The purpose is outlined;

3 Tools, reference documents, and any parts are listed;
4 Safety and operating cautions are prominently displayed;
5 A location is clearly provided for the maintenance mechanic to
indicate performance as either satisfactory or deficient. If deficient,
20 Fundamental Requirements of Effective Preventive/Predictive Maintenance
details are written in the space provided at the bottom for planning
further work.
The procedure may be printed on a reusable, plastic-covered card that can
be pulled from the file, marked, and returned when the work order is com-
plete; on a standard preprinted form; or on a form that is uniquely printed by
computer each time a related work order is prepared. Whatever the medium
of the form, it should be given to the preventive maintenance craftsperson
together with the work order so that he has all the necessary information
at his fingertips. The computer version has the advantage of single-point
control that may be uniformly distributed to many locations. This makes it
easy for an engineer at headquarters to prepare a new procedure or to make
any changes directly on the computer and have them instantly available to
any user in the latest version.
Two slightly different philosophies exist for accomplishing the unscheduled
actions that are necessary to repair defects found during inspection and
preventive maintenance. One is to fix them on the spot. The other is to
identify them clearly for later corrective action. If a “priority one” defect
that could hurt a person or cause severe damage is observed, the equipment
should be immediately stopped and “46 red tagged” so that it will not be
used until repairs are made. Maintenance management should establish a
guideline such as, “Fix anything that can be corrected within ten minutes,
but if it will take longer, write a separate work request.” The policy time
limit should be set based on:
1 Travel time to that work location;
2 Effect on production;

3 Need to keep the craftsperson on a precise time schedule.
The inspector who finds them can effect many small repairs the most quickly.
This avoids the need for someone else to travel to that location, identify the
problem, and correct it. And it provides immediate customer satisfaction.
More time-consuming repairs would disrupt the inspector’s plans, which
could cause other, even more serious problems to go undetected. The
inspector is like a general practitioner, who performs a physical exam and
may give advice on proper diet and exercise but who refers any problems
he may find to a specialist.
The inspection or preventive maintenance procedure form should have
space where any additional action required can be indicated. When the
Fundamental Requirements of Effective Preventive/Predictive Maintenance 21
procedure is completed and turned into maintenance control, the planner
or scheduler should note any additional work required and see that it gets
done according to priority.
Estimating Time
Since inspection or preventive maintenance is a standardized procedure
with little variation, the tasks and time required can be accurately esti-
mated. Methods of developing time estimates include consideration of such
resources as:
1 Equipment manufacturers’ recommendations;
2 National standards such as Chilton’s on automotive or Means’ for
facilities;
3 Industrial engineering time-and-motion studies;
4 Historical experience.
Experience is the best teacher, but it must be carefully critiqued to make sure
that the “one best way” is being used and that the pace of work is reasonable.
The challenge in estimating is to plan a large percentage of the work (prefer-
ably at least 90%) so that the time constraints are challenging but achievable
without a compromise in high quality. The trade-off between reasonable

time and quality requires continuous surveillance by experienced supervi-
sors. Naturally, if a maintenance mechanic knows that his work is being
time studied, he will follow every procedure specifically and will method-
ically check off each step of the procedure. When the industrial engineer
goes away, the mechanic will do what he feels are necessary items, in an
order that may or may not be satisfactory. As discussed earlier in regard
to motivation, an experienced preventive maintenance inspector mechanic
can vary performance as much as 50% either way from the standard without
most maintenance supervisors recognizing a problem or opportunity for
improvement. Periodic checking against national or time-and-motion stan-
dards, as well as trend analysis of repetitive tasks, will help keep preventive
task times at a high level of effectiveness.
Estimating Labor Cost
Cost estimates follow from time estimates simply by multiplying the hours
required by the required labor rates. Beware of coordination problems
where multiple crafts are involved. For example, one Fortune 100 company
22 Fundamental Requirements of Effective Preventive/Predictive Maintenance
has trade jurisdictions that require the following personnel in order to
remove an electric motor: a tinsmith to remove the cover, an electrician
to disconnect the electrical supply, a millwright to unbolt the mounts, and
one or more laborers to remove the motor from its mound. That situation
is fraught with inefficiency and high labor costs, since all four trades must
be scheduled together, with at least three people watching while the fourth
is at work. The cost will be at least four times what it could be, and is often
greater if one of the trades does not show up on time. The best a scheduler
can hope for is if he has the latitude to schedule the cover removal at, say,
8:00
A.M., and the other functions at reasonable time intervals thereafter:
electrician at 9:00, millwright at 10:00, and laborers at 11:00.
It is recommended that estimates be prepared on “pure” time. In other

words, the exact hours and minutes that would be required under perfect
scheduling conditions should be used. Likewise, it should be assumed that
equipment would be immediately available from production. Delay time
should be reported, and scheduling problems should be identified so that
they can be addressed separately from the hands-on procedure times. Note
that people think in hours and minutes, so one hour and ten minutes is
easier to understand than 1.17 hours.
Estimating Materials
Most parts and materials that are used for preventive maintenance are
well known and can be identified in advance. The quantity of each item
planned should be multiplied by the cost of the item in inventory. The
sum of those extended costs will be the material cost estimate. Consum-
ables such as transmission oil should be enumerated as direct costs, but
grease and other supplies used from bulk should be included in overhead
costs.
Scheduling
Scheduling is, of course, one of the advantages to doing preventive mainte-
nance over waiting until equipment fails and then doing emergency repairs.
Like many other activities, the watchword should be “PADA,” which stands
for “Plan a Day Ahead.” In fact, the planning for inspections and preventive
activities can be done days, weeks, and even months in advance in order to
assure that the most convenient time for production is chosen, that mainte-
nance parts and materials are available, and that the maintenance workload
is relatively uniform.
Fundamental Requirements of Effective Preventive/Predictive Maintenance 23
Scheduling is primarily concerned with balancing demand and supply.
Demand comes from the equipment’s need for preventive maintenance.
Supply is the availability of the equipment, craftspeople, and materials that
are necessary to do the work. Establishing the demand is partially covered in
the chapters on on-condition, condition monitoring, and fixed interval pre-

ventive maintenance tasks. Those techniques identify individual equipment
as candidates for PM.
Coordination with Production
Equipment is not always available for preventive maintenance just when
the maintenance schedulers would like it to be. An overriding influence
on coordination should be a cooperative attitude between production and
maintenance. This is best achieved by a meeting between the maintenance
manager and production management, including the foreman level, so that
what will be done to prevent failures, how this will be accomplished, and
what production should expect to gain in uptime may all be explained.
The cooperation of the individual machine operators is of prime impor-
tance. They are on the spot and most able to detect unusual events that
may indicate equipment malfunctions. Once an attitude of general coop-
eration is established, coordination should be refined to monthly, weekly,
daily, and possibly even hourly schedules. Major shutdowns and holidays
should be carefully planned so any work that requires “cold” shutdown can
be done during those periods. Maintenance will often find that they must
do this kind of work on weekends and holidays, when other persons are
on vacation. Normal maintenance should be coordinated according to the
following considerations:
1 Maintenance should publish a list of all equipment that is needed
for inspections, preventive maintenance, and modifications, and the
amount of cycle time that such equipment will be required from
production.
2 A maintenance planner should negotiate the schedule with production
planning so that a balanced workload is available each week.
3 By Wednesday of each week, the schedule for the following week should
be negotiated and posted where it is available to all concerned; it should
be broken down by days.
4 By the end of the day before the preventive activity is scheduled, the

maintenance person who will do the PM should have seen the first-line
24 Fundamental Requirements of Effective Preventive/Predictive Maintenance
production supervisor in charge of the equipment to establish a specific
time for the preventive task.
5 The craftsperson should make every effort to do the job according to
schedule.
6 As soon as the work is complete, the maintenance person should notify
the production supervisor so that the equipment may be put back into
use.
Overdue work should be tracked andbrought up-to-date. Preventive mainte-
nance scheduling should make sure that the interval is maintained between
preventive actions. For example, if a preventive task for May is done on the
thirtieth of the month, the next monthly task should be done during the
last week of June. It is foolish to do a preventive maintenance task on May
30th and another June 1st, just to be able to say one was done each month.
In the case of preventive maintenance, the important thing is not the score
but how the game was played.
Assuring Completion
A formal record is desirable for every inspectionand preventive maintenance
job. If the work is at all detailed, a checklist should be used. The completed
checklist should be returned to the maintenance office on completion of
the work. Any open preventive maintenance work orders should be kept
on report until the supervisor has checked the results for quality assurance
and signed off approval. Modern computer technology with handheld com-
puters and pen-based electronic assistants permits paperless checklists and
verification. In many situations, a paper work order form is still the most
practical media for the field technician. The collected data should then be
entered into a computer system for tracking.
Record Keeping
The foundation records for preventive maintenance are the equipment files.

In a small operation with less than 200 pieces of complex equipment, the
records can easily be maintained on paper. The equipment records provide
information for purposes other than preventive maintenance. The essential
items include:
●
Equipment identification number;
●
Equipment name;
Fundamental Requirements of Effective Preventive/Predictive Maintenance 25
●
Equipment product/group/class;
●
Location;
●
Use meter reading;
●
PM interval(s)
●
Use per day;
●
Last PM due;
●
Next PM due;
●
Cycle time for PM;
●
Crafts required, number of persons, and time for each;
●
Parts required.
Back to Basics

Obviously, effective maintenance management requires much more than
these fundamental tasks. However, these basic tasks must be the foundation
of every successful maintenance program. The addition of other tools, such
as CMMS, predictive maintenance, etc., cannot replace them.
3 Maintenance Skills Assessment
Introduction
A maintenance skills assessment is a valuable tool in determining the
strengths and weaknesses of an individual or a given group of employ-
ees in order to design a high-impact training program that targets those
documented needs. Maintenance personnel have often found it difficult to
upgrade their technical skills because much that is available is redundant
or does not take their current skill level into consideration. An assessment
is designed to eliminate those problems by facilitating the construction of
customized training paths for either individuals or the group based upon
demonstrated existing knowledge and skills. When used in conjunction with
a job task analysis, a gap analysis can be performed to determine both what
skills are needed in order to perform the job effectively and what skills those
in the workforce presently have.
Definition of a Skills Assessment
A maintenance skills assessment consists of a series of written tests, per-
formance exercises, and identification activities selected from a listing of
mechanical basic skill areas. In this chapter maintenance mechanics will be
able to assess their maintenance knowledge only because skills can only be
assessed through a hands-on assessment. However, the knowledge assess-
ment is the prerequisite for all skills. The written assessment in this chapter
is written at an eighth-grade level (maintenance mechanics, in most indus-
tries, must be able to read proficiently at least at the 12-year twelfth-grade
level). A maintenance person without the knowledge required for a specific
skill can be assured mistakes will be made in mechanical judgment and abil-
ity and thus will cause equipment failures. This knowledge assessment will

not cover all skill areas covered in this book but will cover chapters that are
considered the mechanical basics.
Maintenance Skills Assessment 27
Knowledge Assessment
This knowledge assessment is directed to the following skills. The answers
will be provided in Appendix A at the end of the book. A minimum score
of 90% in each skill area should be considered acceptable in most cases.
However, some skill areas could require a higher score if the risk of failure
due to a knowledge gap is high. In all areas of maintenance, a maintenance
person must know the risk.
The knowledge assessment will be performed in the following skills areas:
●
Safety
●
Lubrication
●
Bearings
●
Chain Drives
●
Belt Drives
●
Hydraulics
●
Couplings
Knowledge Assessment
The assessment is multiple choice. Select the best answer. Do not look at
the answers until you have answered all the questions.
Knowledge Area: Safety
1 What term is used to describe places where moving parts meet or come

near each other?
A. Guard
B. Closer
28 Maintenance Skills Assessment
C. Pinch points
D. Assembly point
2 What is another name for back-and-forth motion?
A. Reciprocating motion
B. Away
C. Advancing lateral
D. None of the above
3 What is the term “point of operation?”
A. The section of the process where the machine centers meet
B. The main focus of process
C. The place where the raw material or work-piece is processed by a
machine
D. A point where operators cannot see
4 If a bench grinder is equipped with safety guards, is it necessary for you
to wear personal protective equipment?
A. Yes
B. No
5 What type of machine guard limits the operator’s access to the danger
zone?
A. Safety chain
B. E-stop
C. A barrier guard
D. None of the above
6 What type of machine guard prevents access to the danger zone
altogether?
A. An enclosure guard

B. Safety chain
C. Barrier guard
D. None of the above
7 What kind of guards cannot be moved when a machine is in operation?
A. Barrier guards
B. Fixed guards
C. E-stop guards
D. None of the above
Maintenance Skills Assessment 29
8 What type of guard prevents a machine from operating when the guard
is opened or removed?
A. Barrier guard
B. Tapeless guard
C. An interlocking guard
D. None of the above
9 What type machine guard is capable of physically pulling an operator’s
hands out of the danger zone?
A. An automatic guard
B. Barrier guard
C. Restrictive guard
D. None of the above
10 When will a presence-sensing guard stop a machine?
A. When a person is located outside of the danger zone
B. When a light signals a safety alert
C. There is no such item
D. When a person or object enters the danger zone
11 What kind of controls does a machine have if the operator must remove
both hands from the danger zone in order to start the machine?
A. Hand-free controls
B. Two-hand trip controls

C. Standard controls
D. Automatic controls
12 What kinds of tools make it unnecessary for an operator to reach into
the danger zone?
A. Hand-extraction tools
B. Local guarding tools
C. Feeding and extracting tools
D. None of the above
13 Under what conditions would you remove someone else’s lock from a
lockout device?
A. When plant manager or maintenance manager approves
B. When the person that installed the lockout cannot be found after
30 minutes
C. When you think it is OK to do so safely
D. According to your plant’s lockout procedure
30 Maintenance Skills Assessment
14 What must your employer provide in addition to the appropriate PPE?
A. Training in its use
B. Safety bulletins
C. Training material and trainers
D. None of the above
15 What is your responsibility before using PPE?
A. None
B. You must inspect it
C. Locate all documents controlling it
D. You must report its condition to your supervisor
16 Why should you avoid loose-fitting clothing in the plant?
A. It can create a barrier from sharp parts
B. It can get caught in moving parts
C. It is unprofessional

D. None of the above
17 What should you do if you accidentally come in contact with a dangerous
chemical?
A. It depends on the chemical
B. Report to the safety director
C. Shower for at least 15 minutes to rinse thoroughly
D. None of the above
18 How much clearance should hard-hat webbing provide between your
head and the top of the shell?
A. Close as possible
B.
1
2
"
C. Does not matter
D. 1"
19 How can you keep dust and liquids from reaching your eyes from any
direction?
A. By wearing safety goggles
B. By wearing safety glasses
C. By wearing a face shield
D. Any of the above
Maintenance Skills Assessment 31
20 What units are used to measure noise?
A. Trebels
B. Decibels
C. Milibars
D. None of the above
Knowledge Area: Lubrication
1 A lubricant’s viscosity is rated by what type of unit?

A. SSU
B. SAE
C. ISA
D. LVU
2 A lubricant with high viscosity has a:
A. High speed.
B. High temperature.
C. High resistance to flow.
D. High resistance to breakdown.
3 A low-viscosity lubricant:
A. Provides good cushioning for machine shock loads.
B. Can flow into tight spaces for better lubrication.
C. Does not carry heat away as well as a high-viscosity lubricant.
D. Costs less than a high-viscosity lubricant.
4 What are two disadvantages of high-viscosity lubricants?
A. They are expensive and cannot be used on high-speed motors.
B. They break down quickly and are difficult to apply.
C. They do not flow well and do not carry heat away well.
D. They do not protect against abrasive action of dirt, and they break
down quickly.
5 Multiple-viscosity lubricants differ from single-viscosity lubricants
because:
A. They have special additives that extend their effective temperature
range.
B. They are best within a very narrow temperature range.
32 Maintenance Skills Assessment
C. They will never degrade under high temperatures.
D. They last longer.
6 One advantage of multiple-viscosity lubricants is that:
A. They flow better at medium range temperatures than at either

extreme.
B. They have a high bearing capacity.
C. They have a broad working temperature range.
D. They do not break down in the presence of water.
7 Which of the following is NOT a factor affecting the selection of a
lubricant?
A. Machine speed
B. Environmental humidity
C. Operating temperature
D. Environmental temperatures
8 When choosing a lubricant, you want:
A. The lubricant to stay thin at high temperatures.
B. The lubricant to thicken at low temperatures.
C. The lubricant to thin at low temperatures.
D. The lubricant to maintain effective viscosity at its highest rated
temperatures.
9 An oil cooler is used to:
A. Add heat to the oil to enable it to flow better at low temperatures.
B. Add heat to the oil to keep it from thinning at high temperatures.
C. Remove heat from the oil to prevent it from thinning at high
temperatures.
D. Remove heat from the oil to prevent it from thickening at low
temperatures.
10 What function do detergent additives in lubricants perform?
A. Keep metal surfaces clean
B. Keep the lubricant clean
C. Minimize the amount of foaming
D. All of the above
11 An anti-oxidation additive in a lubricant:
A. Controls the level of dirt.

B. Controls the amount of mixing with air.
Maintenance Skills Assessment 33
C. Controls the level of foaming.
D. Prevents the lubricant from mixing with metal particles.
12 As a mechanic, you observe that a machine bearing is extremely hot and
becoming discolored as it operates. Your conclusion is that the:
A. Lubricant is contaminated by water.
B. Bearing is about to seize.
C. Lubricant is causing acid corrosion on the bearing.
D. Bearing is not compatible with the lubricant.
13 When cooling an overheated bearing, what should you do first?
A. Wrap the bearing housing in hot, wet rags.
B. Spray cool water on the bearing.
C. Inject cool oil in the bearing.
D. Wrap the bearing housing in cool, wet rags.
14 Oil returning to the sump is visually cloudy and foaming. You conclude
that the oil is:
A. Contaminated with soot.
B. Contaminated with water.
C. Contaminated with metal particles.
D. In need of detergent additives.
15 Undesired oil misting can be reduced by:
A. Increasing the temperature of the oil.
B. Increasing the speed of the machine.
C. Increasing the viscosity of the oil.
D. Reducing the viscosity of the oil.
16 A grease cup is defined as a:
A. Cup filled with grease that screws onto a fitting.
B. Timed lubrication system controlled by a rotating cam.
C. Gravity system that forces lubricant onto or into the area needing

lubrication.
D. Fitting that applies oil in droplet form.
17 A lubricating system used in low-speed applications in which a needle
valve meters a steady rate of lubricant to a machine without recycling
the lubricant is a(n):
A. Dip lubricator.
B. Shot lubricator.
34 Maintenance Skills Assessment
C. Drip lubricator.
D. Oil sump.
18 A lubrication system in which the componentneeding lubrication rotates
through an enclosed housing containing oil and carries the oil to other
components is called a(n):
A. Dip lubricator.
B. Shot lubricator.
C. Drip lubricator.
D. Oil sump.
19 In a force-feed lubrication system, lubricant is moved to the component
needing lubrication by a:
A. Cooler.
B. Pump.
C. Filter.
D. Bearing.
20 What is the most undesirable by-product of oil misting?
A. Bearing failure
B. Shaft damage
C. Explosion potential
D. Oil breakdown
Knowledge Area: Bearings
1 The two basic categories of bearings are:

A. Plain and antifriction.
B. Ball and roller.
C. Journal and ball.
D. Pillow-block and roller.
2 Bearings:
A. Are found in machines with moving parts.
B. Function as guides.
C. Help reduce the friction between moving parts.
D. All of the above.
Maintenance Skills Assessment 35
3 Thrust bearings:
A. Support axial loads on rotating members.
B. Support radial loads on rotating members.
C. Both A and B.
D. None of the above.
4 Antifriction bearings:
A. Contain balls.
B. Contain rollers.
C. Will run hot if they are overlubricated.
D. All of the above.
5 Bearing lubrication systems include:
A. Lubrication by hand.
B. Central grease systems.
C. Pressure-feed oil systems.
D. All of the above.
6 Plain bearings operate by:
A. Separating the races with balls or rollers.
B. Using an air gap.
C. Hydraulics.
D. Running on a film of lubricant.

7 Antifriction bearings operate by:
A. Separating the races with balls or rollers.
B. Using an air gap.
C. Hydraulics.
D. Running on a film of lubricant.
8 Roller bearings are used over ball bearings for which of the following
situations?
A. High-speed applications
B. High-load applications
C. Wet environments
D. Mobile equipment engines
9 Bearing clearance can be described as:
A. The space between the rolling elements and the races.
B. The allowed difference between the shaft size and the bearing inner
race.
C. The allowed differences between bearing inner and outer race.
D. None of the above.
36 Maintenance Skills Assessment
10 Shaft tolerance can be defined as:
A. The allowed difference between the shaft size and the bearing inner
race.
B. The force applied during installation.
C. The space between the rolling elements and the races.
D. None of the above.
11 The preferred method for installing an antifriction bearing is:
A. With a sledge hammer.
B. To sand down the shaft until the bearing slides on.
C. With a bearing heater.
D. Both B and C.
12 When tightening the lock-nut on a spherical roller bearing, the preferred

tool is:
A. A spanner wrench.
B. A bearing heater.
C. A hammer and punch.
D. None of the above.
13 The bearing best suited for both radial and thrust loads is a
bearing.
A. tapered-sleeve
B. linear-motion
C. needle
D. tapered-roller
14 A bearing lubricated with oil is capable of
speeds than the same
bearing lubricated with grease.
A. lower
B. higher
C. the same
D. different
15 As you tighten the nut on a spherical-roller bearing, the space between
the race and the rolling element:
A. Increases.
B. Decreases.
C. Remains the same.
D. Develops cracks.
Maintenance Skills Assessment 37
16 On a metric bearing with the number 7307, the ID of the bearing is:
A. 35 mm.
B. 7 mm.
C. .035".
D. .007".

17 To convert the metric shaft size of a bearing to inches, you multiply the
millimeters by:
A. 5.
B. 39.
C. .03937.
D. .05.
18 A failed bearing that has a cracked inner race probably failed
because:
A. the shaft was too large.
B. of a lack of lubricant.
C. the operator failed to do the proper inspection.
D. of overlubrication.
19 An antifriction bearing can run hot because:
A. of overlubrication.
B. it is about to fail.
C. of excessive load.
D. all of the above.
20 A 20% increase in bearing load, can result in a
% decrease in
bearing life.
A. 20
B. 100
C. 50
D. 10
Knowledge Area: Chain Drives
1 What is the maximum elongation that a roller chain can tolerate before
it should be replaced?
A. 10%
B. 3 inches
38 Maintenance Skills Assessment

C. 3%
D.
3
16
inch per ft. of chain
2 What causes roller fatigue?
A. Lack of lubrication
B. Contamination
C. Improper chain tension
D. All of the above
3 What problems will chain misalignment cause?
A. Side plate wear
B. Sprocket wear
C. Pin wear
D. Chain break
4 What are the two most important factors in the life of a silent chain
drive?
A. Lubrication and alignment
B. Lubrication and tension
C. Tension and alignment
D. All of the above
5 What type of machine guard limits the operator’s access to the danger
zone?
A. Safety chain
B. E-stop
C. A barrier guard
D. None of the above
6 What type of machine guard prevents access to the danger zone
altogether?
A. An enclosure guard

B. Safety chain
C. Barrier guard
D. None of the above
7 Name the two main groups of mechanical couplings:
A. Rigid and flexible.
B. Chain and gear.
C. Grid and Lovejoy.
D. Spring and centrifugal.
Maintenance Skills Assessment 39
8 Large fans are typically powered in what way?
A. Motor and belts
B. Motor and chain drive
C. Motor direct drive
D. Motor, gearbox, and belts
9 Which type of conductivity cells are usually equipped with a safety chain
to prevent the cell from blowing out?
A. Immersions
B. Insertion
C. Flow
D. Screw-in
10 Chain-linked fences should be topped with:
A. Three strands of electrically energized wire.
B. Barbed wire.
C. A skirt of the same material that kicks back 45 degrees and extends
18 inches.
D. None of the above.
11 What are the two links that make up a standard roller chain?
A. Roller, rigid
B. Roller, pin
C. Master, half

D. Offset, half
12 On a roller chain with a designation of 35, what do the 3 and the
5 designate?
A. 3 is the size in inches; 5 is the duty
B. 3 is the duty; 5 is the size in thousandths of an inch
C. 3 is the size in eighths of an inch; 5 means a rollerless chain
D. 3 is the size; 5 means heavy duty
13 What is the maximum elongation that a roller chain can tolerate before
it should be replaced?
A. 10%
B. 3 inches
C. 3%
D.
3
16
inch per ft. of chain
40 Maintenance Skills Assessment
14 What causes roller fatigue?
A. Lack of lubrication
B. Contamination
C. Improper chain tension
D. All of the above
15 What problems will chain misalignment cause?
A. Side plate wear
B. Pin wear
C. Chain break
D. All of the above
16 What are the two most important factors in the life of a silent chain drive?
A. Lubrication and alignment
B. Lubrication and tension

C. Tension and alignment
D. Tension and speed
17 Name the two main groups of mechanical couplings.
A. Rigid and flexible
B. Chain and gear
C. Grid and Lovejoy
D. Spring and centrifugal
18 What type of machine guard limits the operator’s access to the danger
zone?
A. Safety chain
B. E-stop
C. A barrier guard
D. None of the above
19 What type of machine guard prevents access to the danger zone
altogether?
A. An enclosure guard
B. Safety chain
C. Barrier guard
D. None of the above
20 What is the tension or slack a roller chain is recommended to have?
A. 10% slack between centers
B.
1
2
inch slack
C. 5% slack between centers
D. 2% slack between centers
Maintenance Skills Assessment 41
Knowledge Area: Belt Drives
1 Of the following, what are the four main types of belt drives?

A. V-belt; flat belt; timing belt; ribbed belt
B. Straight belt; V-belt; gear belt; ribbed belt
C. Rubber; vitron; buna-n; teflon
D. Round belt; dual face belt; V-belt; multibelt
2 Identify routine maintenance performed on flat belts.
A. Tensioning
B. Cleaning
C. Dressing
D. Both A and B
3 Which of the following is an acceptable V-belt installation process?
A. Reduce center-to-center distance of the pulleys.
B. Use a pry bar to slide the belt over the pulleys.
C. Tension the belt until your hand bounces off the belt.
D. All of the above.
4 Which of the following contribute to rapid belt wear?
A. Oil, dirt, heat, and alignment
B. Water, dirt, sunlight, and tension
C. Guarding, shielding, reflection, and direction
D. Sunlight, dry-rot, mold, and water
5 Why do timing or gear belts not require high tension?
A. They do not require tensioning.
B. The material they are made of reduces slippage.
C. They provide slip-proof engagement.
D. There is not load fluctuation.
6 Different speeds are required for various materials when cutting with a
band saw. How is saw speed adjusted?
A. Set the speed indicator to the desired rpm and start the machine.
B. Adjust the belt tensioner and start the machine.
C. Start the machine and adjust the speed indicator.
D. Dial in the correct job selector and start the machine.

7 Belt drives are designed to transmit power between a drive unit and a:
A. Conveyor belt.
B. Motor.
42 Maintenance Skills Assessment
C. Driven unit.
D. Roller.
8 A drive belt with the designation “XL” would indicate which of the
following types?
A. Cogged, fractional horsepower
B. Conventional V-belt
C. Narrow V-belt
D. Positive drive belt
9 A drive belt with the designation “C” would indicate which of the
following types?
A. Power band belt
B. Conventional V-belt
C. Narrow V-belt
D. Fractional horsepower
10 A drive belt with the designation “V” would indicate which of the
following types?
A. Positive drive belt
B. Conventional V-belt
C. Narrow V-belt
D. Fractional horsepower
11 A “C ” belt with a nominal length of 60 inches is
4
10
" long. What
identification should be marked on the belt?
A. C410

B. C60/4
C. C64
D. C56
12 When replacing one of a set of belts, the mechanic should:
A. Replace the worn belt only.
B. Replace the worn belt and the belt closest to the drive motor.
C. Replace all of the belts.
D. Replace the worn belt and the belt farthest from the drive motor.
13 What criteria should be used to determine if a belt needs to be replaced?
A. The belt protrudes above the top of the sheave no more than
1
16
".
B. The belt is flush with the top of the sheave groove.
C. The belt is recessed more than
1
16
" into the groove sheave.
D. The belt is recessed more than
1
8
" into the groove sheave.
Maintenance Skills Assessment 43
14 The length of belt is determined by its:
A. Pitch line.
B. V-line.
C. Standard line.
D. None of the above.
15 When “timing” is a critical consideration with a belt, which of the
following is typically used?

A. Joined belt
B. V-belt
C. Cogged belt
D. Positive drive belt
16 Regarding sheave grove angle, which of the following statements is
correct?
A. Smaller diameter sheaves have less groove angle than larger diame-
ter grooves.
B. Larger diameter sheaves have less groove angle than smaller diame-
ter sheaves.
C. Groove angles are not affected by sheave diameter.
D. Can be compensated for by adjusting belt tension.
17 Which of the following conditions can cause excessive belt wear?
A. Dirty operating conditions
B. Improper sheave alignment
C. Improper tensioning
D. All of the above
Knowledge Area: Hydraulics
1 What function does a reservoir serve in a hydraulic system?
A. Stores surplus of oil
B. Cools the oil
C. Cleans the oil
D. A, B, and C
2 Why is there a baffle in a hydraulic reservoir?
A. To prevent baffling
B. To assist in cleaning and cooling of the oil
C. To keep the oil level the same
D. To prevent overpressurization of the reservoir